1. Field of the Invention
The present invention relates to a position-retaining device for persons whose bodies or body parts are required to be retained in a particular position or attitude and, more particularly, to a position-retaining material which can be made to conform to the configuration of a person's body or body part to provide a position-retaining device which can used to retain the person's body or body part in a required position or attitude with the pressure from the body or body part being distributed uniformly and effectively on the position-retaining device. The present invention also relates to a method of manufacturing the position-retaining device.
2. Background Information
In the field of orthopedic surgery or general surgery, the position of a patient's body or body part is required to be fixed or supported in a constant position for a long period of time during an operation as well as during the recovery period after the operation. There are also situations in which an individual's sitting position must be supported for a long period of time. In order to provide support for or fix the human body or body part in these situations, position-retaining devices such as sand bags, closed-cell foam blocks of various shapes and sizes, restraining belts or a vacuum apparatus have been used.
The use of sand bags, closed-cell foam blocks, restraining belts or the like require a combination of elements having different shapes and sizes which must be uniquely applied for each particular case, and skilled labor is required to apply these devices to patients. Furthermore, since these devices have no elasticity and lack air-permeability, they are uncomfortable for patients. Additionally, the position of the patient's body or body part is likely to be changed when required to be supported in a constant position over a long period of time.
The vacuum apparatus has sphere-like bodies, such as relatively small plastic beads having a diameter of from 1 to 5 mm, which are packed in a hermetically sealed bag. Air is filled in the hermetically sealed bag, and the bag is laid on a bed or an operating table. A patient is then placed on the bag to assume a required position. At this time, the sphere-like bodies are transferred or displaced in the bag in accordance with the shape of the patient's body or body part and the position assumed by the patient. Thereafter, by evacuating the air from the hermetically sealed bag with a vacuum pump to place the interior of the bag in a vacuum state, the sphere-like bodies are prevented from moving and a constant position can be retained.
Although accurate constant support and positioning can be achieved using the foregoing vacuum apparatus, the bag looses its shape when the body or body part of the patient is removed from it. As a result, the foregoing procedure must be repeated in order to support the patient in the required position, which is inconvenient and time consuming. Furthermore, when the vacuum apparatus is used in an operating room, the bag may be accidentally punctured by sharp pointed surgical instruments, such as syringes or surgical knives, thereby destroying the vacuum apparatus and rendering it inoperable. As a result, use of the vacuum apparatus for providing constant support and positioning of a patient's body or body part has not been popular. Additionally, since the bag used in connection with the vacuum apparatus has no elasticity and lacks air-permeability, it is uncomfortable for patients.
Furthermore, in the field of orthopedic surgery such as, for example, surgery involving the lumber vertebra, cervical vertebra, hip joint, etc., rest is required after the surgery for a relatively long period of time during which patients are required to hold a constant posture. For such a purpose, the required patient's posture has been retained using the sand bag, foam block or vacuum apparatus. However, since these position-retaining devices have poor cushioning and elastic properties, patients experience bedsores over the long period of time during which they are required to maintain the constant posture. Furthermore, since these devices have no air-permeability, patients suffer from sweat retention and are exposed to possible skin problems.
Moreover, for patients who can not change their posture by themselves such as, for example, patients who are handicapped cannot support their trunks by themselves, bedridden patients (particularly aged persons) or the like, various types of depressurization mats for preventing bedsores using air, water, gels, or the like, have been used. Although depressurization mats can distribute the body pressure, they have poor position-supporting properties and are unstable and, therefore, are not comfortable for patients. As a result, the need for skilled nursing to care for such patients has increased.
Furthermore, if the body pressure dispersibility of the depressurization mats is improved to provide more comfort to patients, its fixing stability will be reduced. On the other hand, if the fixing stability of the depressurization mats is improved, the body pressure dispersibility will be reduced. Thus the body pressure dispersibility and the fixing stability of depressurization mats cannot be maximized simultaneously.
Moreover, another conventional position-retaining device for retaining the sitting position of seriously handicapped persons is obtained from a mold. During preparation of the mold, the shape of the patient's affected body part is cast using a plaster to make a female mold (negative model). A male mold (positive model) is then prepared from the female mold. The fixing device is then obtained from the male mold using a two component type urethane resin material having cushioning properties. Alternatively, the position-retaining device is obtained using a material which is rigid and has high supporting properties, and a cushion material is then placed thereon.
Although the foregoing position-retaining devices are effective to retain the required posture of patients and handicapped persons, they are not permeable to air, and cannot be used for handicapped persons who lack sufficient physical strength and suffer from neuropathy. Furthermore, preparation of position-retaining devices which require a negative model and a positive model is time consuming and requires increased labor and cost.
Moreover, a material which is comprised of a number of chips bonded by urethane resin and which is formed for positioning a person's body or body part is known (See Japanese Unexamined Patent Publication No. 9-224796).